Clutch transmitting rotating motion

ABSTRACT

A clutch for transmitting rotating motion includes a clutch body, ring flanges positioned an exterior of the clutch body, a belt pulley positioned between the ring flanges and a hydraulic arrangement for producing axial motion and an axial force, causing the belt pulley to be pressed between the ring flanges to transmit rotating motion to the belt pulley. The hydraulic arrangement includes a slight leakage of the hydraulic medium out of the pressurized chamber space to which oil is supplied for engaging clutching, thereby allowing for rapid disengagement of the clutch and circulation of pressurized oil.

FIELD OF THE INVENTION

The present invention is directed to a medium actuated clutch in which aslight leakage of hydraulic medium is arranged out of a pressurizedchamber space to allow rapid disengagement of the clutch and circulationof pressurized oil.

BACKGROUND OF THE INVENTION

Previously known from U.S. Published Patent Application No. B382,290 isa medium actuated clutch where the rotation-transmitting clutch disc anda mobile pressure plate are in a chamber containing the medium. Thechamber is divided into many sub-chambers by the disc and the plate andby means of pressure variations, the pressure plate can be put intomotion and the disc and plate surfaces in abutment against each other tocarry out clutching.

Such a clutch is applicable to cars with automatic transmission with theclutch thereby in the gearbox. In the gearbox there is oil to operatethe clutch and possible oil leakage is of no harm if the leaking oil isflowing directly back into the gearbox. However, a clutch of this kindis not very well fitted for general cases, for instance as a commonshaft clutch and, of course, not as a dry clutch in vehicles.

SUMMARY OF THE INVENTION

A clutch as per this invention offers a new disc clutch assembly.

The most significant advantages of the invention can be considered thatthe thrust bearing can be omitted. It is not needed either with theclutch engaged or disengaged, since the disc shaft needs no supportagainst axial forces. The clutch works with medium of low pressure andshaft packings are needed only to prevent leakage of low pressure mediumleaving the clutch, lower than working pressure. The clutch body stillrotates all the time along with the shaft and the packings are notexposed to wear and tear. The clutch is interconnected with a combustionengine such that driving oil can be conveyed from the lubricating oilpump, and the return oil is easily conveyed along the clutch shaft tothe crankshaft and the crankcase.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention is disclosed with reference the encloseddrawing, where

FIG. 1 is a cross-sectional side view of the clutch;

FIG. 2 is a cross-sectional side view of another clutch; and

FIG. 3 is a cross-sectional view of a clutch interconnected with acombustion engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 the clutch shaft 1 is shown as an actuating shaft from whichthe rotating motion is transmitted by means of the clutch to belt pulley20. The belt pulley 20 is fastened with bearings to rotate with respectto the shaft 1 by means of a ball bearing 12. The belt pulley 20 hasclutch linings 9 on both power transmitting sides. On engaging theclutch, the belt pulley is pressed between flange 8 and body 10 forpower transmission to the belt pulley. Clutch body 10 built about shaft1 contains a cylindrical inner chamber, which is divided into twochambers by a disc 13 in the cylinder. Disc 13 is secured to the shaftsurface so that it cannot slide, at least not past holder 14. The clutchbody rotates always along with shaft 1. This is arranged by rolls 11 inthe shaft splines, which have semi-splines in the the clutch body 10.Shaft 1 and clutch body 10 are interconnected by a bronze ring 3, whichhas a sliding fit with regard to shaft 1. One end of clutch body 10 canbe opened and fitted with a shaft packing 2.

Channels are drilled in shaft 1 for the medium, for instance 16 andreturn oil 17. Pressurized oil is conveyed to chamber 22 and chamber 23and the adjacent areas of shaft packing 2 are connected to returnchannel 17. Shaft channels 16 and 17 are connected to a connection piece6 arranged about shaft 1 and furnished with connections 4 and 5 for bothchannels.

To engage the clutch the pressure is steered to channel 16 and furtherto chamber 22. Since due to holder 14 disc 13 cannot move, body 10 movestowards the belt pulley and due to pressure in chamber 22 the bodyremains in position pressing the belt pulley 20 against flange 8 inorder to sustain the connection. Belt pulley 20 begins to rotate alongwith the shaft and the body. The pressure of chamber 23 is low becauseof the free discharge channel 17,4. Due to rotation of chambers 22,23dynamic pressure is produced into both chambers as a function ofrotative velocity, when the chambers are filled with oil, but thispressure does not tend to move the body portion 10 in the form of theembodiment shown in the figure when both chambers have same rate heavyoil. With the clutch engaged possible oil leaks reaching as far as theshaft packings are conveyed to channel 17 and connection 4. In this casethe clutch does not generate any axial force and accordingly no thrustbearing is needed.

Upon engaging the clutch the access of pressure and oil into channel 16is closed. Since the medium is not compressible, the compressive forcedecreases immediately and the body 10 moves slightly off belt pulley 20and the clutch declutches. Even in this case no axial force remainsactive in the shaft.

FIG. 2 shows a vehicle clutch whose driving part is a clutch disc 26fixed to flywheel 27 slidingly on screws 21. Clutch disc 26 has clutchlinings 9. About screws 21 there are sliding sleeves 24. Shaft 1b havinga flange 25 is working as the driven part. In the embodiment as per FIG.2 an optional track for the oil through a bore to the crankcase 18 isillustrated. From its other end shaft 1b is fastened to flywheel 27center by a bearing 12. Otherwise the clutch is similar to the clutch inFIG. 1.

Due to the clutch function, the construction of its valve is ofsignificance, by means of which valve the pressure to and from chamber22, especially in vehicle use, is adjusted. It must be possible to slidethe clutch with the valve. In the valve a position must be easily found,where by certain oil pressure rate almost as much oil flows into chamber22 as out from it in order to reach an intermediate sliding position forthe clutch. Such spool valves are available.

In order to activate disengagement of the clutch, dynamic pressure canbe utilized, which is formed in chambers 22,23 when the clutch isrotating. It is possible to make at pressure plate 13 a shoulder inshaft 1b, where the shaft diameter gets smaller towards end 15 andfurther on. Then the cross-sectional area of chamber 23 becomes greaterthan that of chamber 22 and immediately, when pressure channel 16 isclosed, a greater force is produced from dynamic pressure in chamber 23than in chamber 22 and the dynamic pressure tends to move body 10 looseand intensifies the disengament. Naturally, it is also possible to putin chamber 23 a spring pressed to make the chamber 23 larger, the effectof which spring is clearly exceeded by the effect of chamber 22pressure. The spring would accelerate disengagement of clutch.

Several clutch discs can be abreast pressed by the same body portion andan advantageous embodiment is also that several clutches are arranged onthe same shaft 1 and for each of them an individual drive wheel, forinstance a belt pulley, and by control of working pressure the requiredclutch 1 and belt pulley of shaft are selected to pull. Then powertransmissions can be formed in using belt pulleys of different size andby means of the clutch one of them is chosen to pull while the otherbelt pulley clutches are steered into disengaged position.

FIG. 3 shows a clutch as per the invention interconnected with acombustion engine. The clutch disc includes a flange 38 with clutchlining pressed against the flywheel in the crankshaft end by a ringflange fixed to moving clutch body 32. From clutch disc 38 the rotatingmotion is transmitted by means of a conical box 30 to a secondary shaft31. The clutch shaft is an extension of the crankshaft. On the clutchshaft surface the clutch body 32 glides by means of oil pressure.Hydraulic oil is conveyed along channel 37 into the cylinder chamber tothe left hand side of piston 13. Oil pressure moves the clutch intodisengaged position in moving the body 32. The clutch is disengaged bylack of pressure. In the embodiment there can be continuous slight oilleakage from piston 13 mouth 29 to the return side. With this embodimentrapid disengagment of the clutch is achieved as soon as the feed of oilpressure side is cut off. Further, with oil circulation other advantagesare achieved, such as prevention of oil warming-up or foaming in thecylinder chamber.

There is in the oil return channel a ball valve 28 disengaging by lowpressure, for instance 0.5 bar. This prevents the cylinder chambers fromgetting empty on stopping the engine. Since the chambers on both sidesof piston 13 are always filled with oil, the clutch is applicable assoon as the engine is started.

In FIG. 3 piston 13 is locked on shaft 36 between the shoulder andsleeve 33. With the adjustment ring 34 the position of body 32 can beregulated to the left for instance according to the wear of the clutchlining. Ring 34 is fixed by a thread on sleeve 33 surface. With ring 35the adjustment is secured on tightening ring 35 against ring 34 by meansof a thread on shaft 36 surface.

The clutch is disengaged also by high rotations when the feed pressureis disconnected, since the piston has a greater area towards theright-hand chamber and only the centrifugal force on the oil thenproduces the pressure into the chambers. Thus, the clutch is disengagedby the impact of pressure.

I claim:
 1. A clutch positionable around a shaft for transmittingrotating motion comprising:a clutch body; ring flanges positioned on anexterior of the clutch body; a belt pulley positioned between said ringflanges; and a hydraulic arrangement for producing axial motion andaxial force for pressing said belt pulley between said ring flanges fortransmitting rotating motion to said belt pulley in order to carry outclutching, the clutch body acting as a cylinder for the hydraulicarrangement and producing axial motion by means of pressurized hydraulicmedium gliding on the shaft for engaging and disengaging clutching, saidhydraulic arrangement including a pressurized chamber space into whichsaid pressurized hydraulic oil is supplied for engaging clutching, aslight leakage of hydraulic medium being arranged out of said chamberspace for allowing rapid disengagement of the clutch and circulation ofpressurized oil.
 2. A clutch according to claim 1 wherein said leakageof hydraulic medium is arranged over a piston through a throttle hole inthe piston.
 3. A clutch according to claim 1 wherein said leakage ofhydraulic medium is arranged out of the pressurized chamber space frombetween the shaft and a slide ring to a return chamber for the medium.4. A clutch according to claim 1 wherein shaft includes channels formedtherein for conveyance of the pressurized medium inside the shaft to thepressurized chamber space and for conveyance of said medium and saidleakage to a return chamber.